1) Field of the Invention
The present invention is directed to energetic materials and in particular to a method for the synthesis of KDNP, a lead-free replacement to lead styphnate.
2) Description of Prior Art
There is growing interest in the manufacture and scale-up of alternative replacements to heavy metal-containing energetic materials based on regulatory changes and clean-up costs associated with heavy metal waste. The compound, potassium 5,7-dinitro-[2,1,3]-benzoxadiazol-4-olate-3-oxide (KDNP), has been qualified by the Navy as a primary explosive and is being developed as a suitable replacement for lead styphnate.
Previous attempts to synthesize KDNP, however, have resulted in bench scale quantities of the compound that required multiple steps for the synthesis of KDNP. For example, the method reported by Fronabarger et al. in U.S. Pat. No. 8,062,443 and “KDNP—A Lead Free Replacement for Lead Styphnate”, Propellants Explos. Pyrotech, 36, pages 459-470, 2011, requires several laboratory operations to convert BTNA to KDNP, including the use of multiple solvents and separation steps in the preparation of KDNP. Therefore, an efficient and commercially viable process is desired for the synthesis and production of larger quantities of KDNP using a minimal number of processing steps.